Static and dynamic seismic source parameter analysis of the Ms6. 9 Qinghai Menyuan earthquake on January 8, 2022

The characteristics of an earthquake can be quantified by source parameters. After an earthquake, it is important to determine the source parameters quickly to study regional tectonic characteristics, the nature of earthquake sources, and the process of earthquake incubation and evolution, and to assess earthquake damage and respond to earthquake emergencies. In this study, the seismic moment and focal mechanism of M(s)6. 9 Qinghai Menyuan earthquake are inverted using the time-domain full moment tensor inversion method, and the corrected radiated seismic energy, energy magnitude, and rupture duration are determined according to the waveforms recorded at the regional and global seismic stations. The results show that (1) The Menyuan earthquake is a strike-slip earthquake with its strike/dip/ rake 194 degrees 787/175 degrees and 285 degrees/85 degrees/3 degrees for nodal planes I and II, respectively. The moment magnitude M-w is 6. 6 with an optimal source depth of 3 km. A combination of the dynamic parameters of the earthquake source indicates that nodal plane II is the fault plane of the earthquake; (2) The radiated seismic energy E-R is computed to be 4.3/10(14)J, the corresponding M-e is 6. 8, which is significantly greater than M-w; (3) The earthquake shows bilateral rupture characteristics, and the rupture duration is 11 s; (4) Considering all above parameters together, we can obtain values of the energy-to-moment ratio E-R/M-0 is 5.1x10 (5), the apparent stress, stress drop and the radiated seismic energy enhancement factor that describes the rupture complexity is 1. 53 MPa, 6. 58 MPa and 34, respectively; (5) Combining the static and dynamic source parameters of this earthquake, it can be concluded that the Menyuan earthquake is a strike-slip type earthquake with a large dip of the fault plane and high energy release efficiency. In general, such earthquakes cause more damage than earthquakes of the same magnitude.